Should I?

I am wibbling over buying one of these:

Solarventi Solar power dehumidifer

 If it works it would be the answer to so many problems.

 The theory is simple.  When the sun is shining the humidity outside the house, 10 feet off the ground is always drier than the air inside.

 The gadget is an PV panel, attached to a South East facing wall, which powers a fan to draw this relatively drier air into the unit, drive it through the body of the panel, where it is passively warmed, and then push the fresh, dry(er) and warm(er) air into the house at floor level.

The introduced air displaces the stagnant damp(er) air out of the house through the chimney and other leaky bits.

Which means (a) the cottage would be dry(er) and (b) less mouldy and (c) a teeny weeny bit warmer throughout the year and (d) I could close most of the windows that the owl and swallows etc are using.

I have the ideal wall, it's around £500 and Barry would be the ideal man to fit it.

If nothing else - it would be a fascinating experiment!

So - buy or not buy?

ETA - rats, just noticed, they had a 10% discount offer which ran out yesterday...